mirror of
https://github.com/python/cpython.git
synced 2024-12-01 03:01:36 +01:00
732 lines
25 KiB
C
732 lines
25 KiB
C
/* Peephole optimizations for bytecode compiler. */
|
|
|
|
#include "Python.h"
|
|
|
|
#include "Python-ast.h"
|
|
#include "node.h"
|
|
#include "ast.h"
|
|
#include "code.h"
|
|
#include "symtable.h"
|
|
#include "opcode.h"
|
|
|
|
#define GETARG(arr, i) ((int)((arr[i+2]<<8) + arr[i+1]))
|
|
#define UNCONDITIONAL_JUMP(op) (op==JUMP_ABSOLUTE || op==JUMP_FORWARD)
|
|
#define CONDITIONAL_JUMP(op) (op==POP_JUMP_IF_FALSE || op==POP_JUMP_IF_TRUE \
|
|
|| op==JUMP_IF_FALSE_OR_POP || op==JUMP_IF_TRUE_OR_POP)
|
|
#define ABSOLUTE_JUMP(op) (op==JUMP_ABSOLUTE || op==CONTINUE_LOOP \
|
|
|| op==POP_JUMP_IF_FALSE || op==POP_JUMP_IF_TRUE \
|
|
|| op==JUMP_IF_FALSE_OR_POP || op==JUMP_IF_TRUE_OR_POP)
|
|
#define JUMPS_ON_TRUE(op) (op==POP_JUMP_IF_TRUE || op==JUMP_IF_TRUE_OR_POP)
|
|
#define GETJUMPTGT(arr, i) (GETARG(arr,i) + (ABSOLUTE_JUMP(arr[i]) ? 0 : i+3))
|
|
#define SETARG(arr, i, val) arr[i+2] = val>>8; arr[i+1] = val & 255
|
|
#define CODESIZE(op) (HAS_ARG(op) ? 3 : 1)
|
|
#define ISBASICBLOCK(blocks, start, bytes) \
|
|
(blocks[start]==blocks[start+bytes-1])
|
|
|
|
|
|
#define CONST_STACK_CREATE() { \
|
|
const_stack_size = 256; \
|
|
const_stack = PyMem_New(PyObject *, const_stack_size); \
|
|
load_const_stack = PyMem_New(Py_ssize_t, const_stack_size); \
|
|
if (!const_stack || !load_const_stack) { \
|
|
PyErr_NoMemory(); \
|
|
goto exitError; \
|
|
} \
|
|
}
|
|
|
|
#define CONST_STACK_DELETE() do { \
|
|
if (const_stack) \
|
|
PyMem_Free(const_stack); \
|
|
if (load_const_stack) \
|
|
PyMem_Free(load_const_stack); \
|
|
} while(0)
|
|
|
|
#define CONST_STACK_LEN() (const_stack_top + 1)
|
|
|
|
#define CONST_STACK_PUSH_OP(i) do { \
|
|
PyObject *_x; \
|
|
assert(codestr[i] == LOAD_CONST); \
|
|
assert(PyList_GET_SIZE(consts) > GETARG(codestr, i)); \
|
|
_x = PyList_GET_ITEM(consts, GETARG(codestr, i)); \
|
|
if (++const_stack_top >= const_stack_size) { \
|
|
const_stack_size *= 2; \
|
|
PyMem_Resize(const_stack, PyObject *, const_stack_size); \
|
|
PyMem_Resize(load_const_stack, Py_ssize_t, const_stack_size); \
|
|
if (!const_stack || !load_const_stack) { \
|
|
PyErr_NoMemory(); \
|
|
goto exitError; \
|
|
} \
|
|
} \
|
|
load_const_stack[const_stack_top] = i; \
|
|
const_stack[const_stack_top] = _x; \
|
|
in_consts = 1; \
|
|
} while(0)
|
|
|
|
#define CONST_STACK_RESET() do { \
|
|
const_stack_top = -1; \
|
|
} while(0)
|
|
|
|
#define CONST_STACK_TOP() \
|
|
const_stack[const_stack_top]
|
|
|
|
#define CONST_STACK_LASTN(i) \
|
|
&const_stack[const_stack_top - i + 1]
|
|
|
|
#define CONST_STACK_POP(i) do { \
|
|
assert(const_stack_top + 1 >= i); \
|
|
const_stack_top -= i; \
|
|
} while(0)
|
|
|
|
#define CONST_STACK_OP_LASTN(i) \
|
|
((const_stack_top >= i - 1) ? load_const_stack[const_stack_top - i + 1] : -1)
|
|
|
|
|
|
/* Replace LOAD_CONST c1. LOAD_CONST c2 ... LOAD_CONST cn BUILD_TUPLE n
|
|
with LOAD_CONST (c1, c2, ... cn).
|
|
The consts table must still be in list form so that the
|
|
new constant (c1, c2, ... cn) can be appended.
|
|
Called with codestr pointing to the first LOAD_CONST.
|
|
Bails out with no change if one or more of the LOAD_CONSTs is missing.
|
|
Also works for BUILD_LIST and BUILT_SET when followed by an "in" or "not in"
|
|
test; for BUILD_SET it assembles a frozenset rather than a tuple.
|
|
*/
|
|
static int
|
|
tuple_of_constants(unsigned char *codestr, Py_ssize_t n,
|
|
PyObject *consts, PyObject **objs)
|
|
{
|
|
PyObject *newconst, *constant;
|
|
Py_ssize_t i, len_consts;
|
|
|
|
/* Pre-conditions */
|
|
assert(PyList_CheckExact(consts));
|
|
|
|
/* Buildup new tuple of constants */
|
|
newconst = PyTuple_New(n);
|
|
if (newconst == NULL)
|
|
return 0;
|
|
len_consts = PyList_GET_SIZE(consts);
|
|
for (i=0 ; i<n ; i++) {
|
|
constant = objs[i];
|
|
Py_INCREF(constant);
|
|
PyTuple_SET_ITEM(newconst, i, constant);
|
|
}
|
|
|
|
/* If it's a BUILD_SET, use the PyTuple we just built to create a
|
|
PyFrozenSet, and use that as the constant instead: */
|
|
if (codestr[0] == BUILD_SET) {
|
|
PyObject *tuple = newconst;
|
|
newconst = PyFrozenSet_New(tuple);
|
|
Py_DECREF(tuple);
|
|
if (newconst == NULL)
|
|
return 0;
|
|
}
|
|
|
|
/* Append folded constant onto consts */
|
|
if (PyList_Append(consts, newconst)) {
|
|
Py_DECREF(newconst);
|
|
return 0;
|
|
}
|
|
Py_DECREF(newconst);
|
|
|
|
/* Write NOPs over old LOAD_CONSTS and
|
|
add a new LOAD_CONST newconst on top of the BUILD_TUPLE n */
|
|
codestr[0] = LOAD_CONST;
|
|
SETARG(codestr, 0, len_consts);
|
|
return 1;
|
|
}
|
|
|
|
/* Replace LOAD_CONST c1. LOAD_CONST c2 BINOP
|
|
with LOAD_CONST binop(c1,c2)
|
|
The consts table must still be in list form so that the
|
|
new constant can be appended.
|
|
Called with codestr pointing to the BINOP.
|
|
Abandons the transformation if the folding fails (i.e. 1+'a').
|
|
If the new constant is a sequence, only folds when the size
|
|
is below a threshold value. That keeps pyc files from
|
|
becoming large in the presence of code like: (None,)*1000.
|
|
*/
|
|
static int
|
|
fold_binops_on_constants(unsigned char *codestr, PyObject *consts, PyObject **objs)
|
|
{
|
|
PyObject *newconst, *v, *w;
|
|
Py_ssize_t len_consts, size;
|
|
int opcode;
|
|
|
|
/* Pre-conditions */
|
|
assert(PyList_CheckExact(consts));
|
|
|
|
/* Create new constant */
|
|
v = objs[0];
|
|
w = objs[1];
|
|
opcode = codestr[0];
|
|
switch (opcode) {
|
|
case BINARY_POWER:
|
|
newconst = PyNumber_Power(v, w, Py_None);
|
|
break;
|
|
case BINARY_MULTIPLY:
|
|
newconst = PyNumber_Multiply(v, w);
|
|
break;
|
|
case BINARY_TRUE_DIVIDE:
|
|
newconst = PyNumber_TrueDivide(v, w);
|
|
break;
|
|
case BINARY_FLOOR_DIVIDE:
|
|
newconst = PyNumber_FloorDivide(v, w);
|
|
break;
|
|
case BINARY_MODULO:
|
|
newconst = PyNumber_Remainder(v, w);
|
|
break;
|
|
case BINARY_ADD:
|
|
newconst = PyNumber_Add(v, w);
|
|
break;
|
|
case BINARY_SUBTRACT:
|
|
newconst = PyNumber_Subtract(v, w);
|
|
break;
|
|
case BINARY_SUBSCR:
|
|
newconst = PyObject_GetItem(v, w);
|
|
break;
|
|
case BINARY_LSHIFT:
|
|
newconst = PyNumber_Lshift(v, w);
|
|
break;
|
|
case BINARY_RSHIFT:
|
|
newconst = PyNumber_Rshift(v, w);
|
|
break;
|
|
case BINARY_AND:
|
|
newconst = PyNumber_And(v, w);
|
|
break;
|
|
case BINARY_XOR:
|
|
newconst = PyNumber_Xor(v, w);
|
|
break;
|
|
case BINARY_OR:
|
|
newconst = PyNumber_Or(v, w);
|
|
break;
|
|
default:
|
|
/* Called with an unknown opcode */
|
|
PyErr_Format(PyExc_SystemError,
|
|
"unexpected binary operation %d on a constant",
|
|
opcode);
|
|
return 0;
|
|
}
|
|
if (newconst == NULL) {
|
|
if(!PyErr_ExceptionMatches(PyExc_KeyboardInterrupt))
|
|
PyErr_Clear();
|
|
return 0;
|
|
}
|
|
size = PyObject_Size(newconst);
|
|
if (size == -1) {
|
|
if (PyErr_ExceptionMatches(PyExc_KeyboardInterrupt))
|
|
return 0;
|
|
PyErr_Clear();
|
|
} else if (size > 20) {
|
|
Py_DECREF(newconst);
|
|
return 0;
|
|
}
|
|
|
|
/* Append folded constant into consts table */
|
|
len_consts = PyList_GET_SIZE(consts);
|
|
if (PyList_Append(consts, newconst)) {
|
|
Py_DECREF(newconst);
|
|
return 0;
|
|
}
|
|
Py_DECREF(newconst);
|
|
|
|
/* Write NOP NOP NOP NOP LOAD_CONST newconst */
|
|
codestr[-2] = LOAD_CONST;
|
|
SETARG(codestr, -2, len_consts);
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
fold_unaryops_on_constants(unsigned char *codestr, PyObject *consts, PyObject *v)
|
|
{
|
|
PyObject *newconst;
|
|
Py_ssize_t len_consts;
|
|
int opcode;
|
|
|
|
/* Pre-conditions */
|
|
assert(PyList_CheckExact(consts));
|
|
assert(codestr[0] == LOAD_CONST);
|
|
|
|
/* Create new constant */
|
|
opcode = codestr[3];
|
|
switch (opcode) {
|
|
case UNARY_NEGATIVE:
|
|
newconst = PyNumber_Negative(v);
|
|
break;
|
|
case UNARY_INVERT:
|
|
newconst = PyNumber_Invert(v);
|
|
break;
|
|
case UNARY_POSITIVE:
|
|
newconst = PyNumber_Positive(v);
|
|
break;
|
|
default:
|
|
/* Called with an unknown opcode */
|
|
PyErr_Format(PyExc_SystemError,
|
|
"unexpected unary operation %d on a constant",
|
|
opcode);
|
|
return 0;
|
|
}
|
|
if (newconst == NULL) {
|
|
if(!PyErr_ExceptionMatches(PyExc_KeyboardInterrupt))
|
|
PyErr_Clear();
|
|
return 0;
|
|
}
|
|
|
|
/* Append folded constant into consts table */
|
|
len_consts = PyList_GET_SIZE(consts);
|
|
if (PyList_Append(consts, newconst)) {
|
|
Py_DECREF(newconst);
|
|
PyErr_Clear();
|
|
return 0;
|
|
}
|
|
Py_DECREF(newconst);
|
|
|
|
/* Write NOP LOAD_CONST newconst */
|
|
codestr[0] = NOP;
|
|
codestr[1] = LOAD_CONST;
|
|
SETARG(codestr, 1, len_consts);
|
|
return 1;
|
|
}
|
|
|
|
static unsigned int *
|
|
markblocks(unsigned char *code, Py_ssize_t len)
|
|
{
|
|
unsigned int *blocks = (unsigned int *)PyMem_Malloc(len*sizeof(int));
|
|
int i,j, opcode, blockcnt = 0;
|
|
|
|
if (blocks == NULL) {
|
|
PyErr_NoMemory();
|
|
return NULL;
|
|
}
|
|
memset(blocks, 0, len*sizeof(int));
|
|
|
|
/* Mark labels in the first pass */
|
|
for (i=0 ; i<len ; i+=CODESIZE(opcode)) {
|
|
opcode = code[i];
|
|
switch (opcode) {
|
|
case FOR_ITER:
|
|
case JUMP_FORWARD:
|
|
case JUMP_IF_FALSE_OR_POP:
|
|
case JUMP_IF_TRUE_OR_POP:
|
|
case POP_JUMP_IF_FALSE:
|
|
case POP_JUMP_IF_TRUE:
|
|
case JUMP_ABSOLUTE:
|
|
case CONTINUE_LOOP:
|
|
case SETUP_LOOP:
|
|
case SETUP_EXCEPT:
|
|
case SETUP_FINALLY:
|
|
case SETUP_WITH:
|
|
j = GETJUMPTGT(code, i);
|
|
blocks[j] = 1;
|
|
break;
|
|
}
|
|
}
|
|
/* Build block numbers in the second pass */
|
|
for (i=0 ; i<len ; i++) {
|
|
blockcnt += blocks[i]; /* increment blockcnt over labels */
|
|
blocks[i] = blockcnt;
|
|
}
|
|
return blocks;
|
|
}
|
|
|
|
/* Perform basic peephole optimizations to components of a code object.
|
|
The consts object should still be in list form to allow new constants
|
|
to be appended.
|
|
|
|
To keep the optimizer simple, it bails out (does nothing) for code that
|
|
has a length over 32,700, and does not calculate extended arguments.
|
|
That allows us to avoid overflow and sign issues. Likewise, it bails when
|
|
the lineno table has complex encoding for gaps >= 255. EXTENDED_ARG can
|
|
appear before MAKE_FUNCTION; in this case both opcodes are skipped.
|
|
EXTENDED_ARG preceding any other opcode causes the optimizer to bail.
|
|
|
|
Optimizations are restricted to simple transformations occuring within a
|
|
single basic block. All transformations keep the code size the same or
|
|
smaller. For those that reduce size, the gaps are initially filled with
|
|
NOPs. Later those NOPs are removed and the jump addresses retargeted in
|
|
a single pass. Line numbering is adjusted accordingly. */
|
|
|
|
PyObject *
|
|
PyCode_Optimize(PyObject *code, PyObject* consts, PyObject *names,
|
|
PyObject *lineno_obj)
|
|
{
|
|
Py_ssize_t i, j, codelen;
|
|
int nops, h, adj;
|
|
int tgt, tgttgt, opcode;
|
|
unsigned char *codestr = NULL;
|
|
unsigned char *lineno;
|
|
int *addrmap = NULL;
|
|
int new_line, cum_orig_line, last_line, tabsiz;
|
|
PyObject **const_stack = NULL;
|
|
Py_ssize_t *load_const_stack = NULL;
|
|
Py_ssize_t const_stack_top = -1;
|
|
Py_ssize_t const_stack_size = 0;
|
|
int in_consts = 0; /* whether we are in a LOAD_CONST sequence */
|
|
unsigned int *blocks = NULL;
|
|
|
|
/* Bail out if an exception is set */
|
|
if (PyErr_Occurred())
|
|
goto exitError;
|
|
|
|
/* Bypass optimization when the lineno table is too complex */
|
|
assert(PyBytes_Check(lineno_obj));
|
|
lineno = (unsigned char*)PyBytes_AS_STRING(lineno_obj);
|
|
tabsiz = PyBytes_GET_SIZE(lineno_obj);
|
|
if (memchr(lineno, 255, tabsiz) != NULL)
|
|
goto exitUnchanged;
|
|
|
|
/* Avoid situations where jump retargeting could overflow */
|
|
assert(PyBytes_Check(code));
|
|
codelen = PyBytes_GET_SIZE(code);
|
|
if (codelen > 32700)
|
|
goto exitUnchanged;
|
|
|
|
/* Make a modifiable copy of the code string */
|
|
codestr = (unsigned char *)PyMem_Malloc(codelen);
|
|
if (codestr == NULL) {
|
|
PyErr_NoMemory();
|
|
goto exitError;
|
|
}
|
|
codestr = (unsigned char *)memcpy(codestr,
|
|
PyBytes_AS_STRING(code), codelen);
|
|
|
|
/* Verify that RETURN_VALUE terminates the codestring. This allows
|
|
the various transformation patterns to look ahead several
|
|
instructions without additional checks to make sure they are not
|
|
looking beyond the end of the code string.
|
|
*/
|
|
if (codestr[codelen-1] != RETURN_VALUE)
|
|
goto exitUnchanged;
|
|
|
|
/* Mapping to new jump targets after NOPs are removed */
|
|
addrmap = (int *)PyMem_Malloc(codelen * sizeof(int));
|
|
if (addrmap == NULL) {
|
|
PyErr_NoMemory();
|
|
goto exitError;
|
|
}
|
|
|
|
blocks = markblocks(codestr, codelen);
|
|
if (blocks == NULL)
|
|
goto exitError;
|
|
assert(PyList_Check(consts));
|
|
|
|
CONST_STACK_CREATE();
|
|
|
|
for (i=0 ; i<codelen ; i += CODESIZE(codestr[i])) {
|
|
reoptimize_current:
|
|
opcode = codestr[i];
|
|
|
|
if (!in_consts) {
|
|
CONST_STACK_RESET();
|
|
}
|
|
in_consts = 0;
|
|
|
|
switch (opcode) {
|
|
/* Replace UNARY_NOT POP_JUMP_IF_FALSE
|
|
with POP_JUMP_IF_TRUE */
|
|
case UNARY_NOT:
|
|
if (codestr[i+1] != POP_JUMP_IF_FALSE
|
|
|| !ISBASICBLOCK(blocks,i,4))
|
|
continue;
|
|
j = GETARG(codestr, i+1);
|
|
codestr[i] = POP_JUMP_IF_TRUE;
|
|
SETARG(codestr, i, j);
|
|
codestr[i+3] = NOP;
|
|
goto reoptimize_current;
|
|
|
|
/* not a is b --> a is not b
|
|
not a in b --> a not in b
|
|
not a is not b --> a is b
|
|
not a not in b --> a in b
|
|
*/
|
|
case COMPARE_OP:
|
|
j = GETARG(codestr, i);
|
|
if (j < 6 || j > 9 ||
|
|
codestr[i+3] != UNARY_NOT ||
|
|
!ISBASICBLOCK(blocks,i,4))
|
|
continue;
|
|
SETARG(codestr, i, (j^1));
|
|
codestr[i+3] = NOP;
|
|
break;
|
|
|
|
/* Skip over LOAD_CONST trueconst
|
|
POP_JUMP_IF_FALSE xx. This improves
|
|
"while 1" performance. */
|
|
case LOAD_CONST:
|
|
CONST_STACK_PUSH_OP(i);
|
|
j = GETARG(codestr, i);
|
|
if (codestr[i+3] != POP_JUMP_IF_FALSE ||
|
|
!ISBASICBLOCK(blocks,i,6) ||
|
|
!PyObject_IsTrue(PyList_GET_ITEM(consts, j)))
|
|
continue;
|
|
memset(codestr+i, NOP, 6);
|
|
CONST_STACK_RESET();
|
|
break;
|
|
|
|
/* Try to fold tuples of constants (includes a case for lists and sets
|
|
which are only used for "in" and "not in" tests).
|
|
Skip over BUILD_SEQN 1 UNPACK_SEQN 1.
|
|
Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2.
|
|
Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */
|
|
case BUILD_TUPLE:
|
|
case BUILD_LIST:
|
|
case BUILD_SET:
|
|
j = GETARG(codestr, i);
|
|
if (j == 0)
|
|
break;
|
|
h = CONST_STACK_OP_LASTN(j);
|
|
assert((h >= 0 || CONST_STACK_LEN() < j));
|
|
if (h >= 0 && j > 0 && j <= CONST_STACK_LEN() &&
|
|
((opcode == BUILD_TUPLE &&
|
|
ISBASICBLOCK(blocks, h, i-h+3)) ||
|
|
((opcode == BUILD_LIST || opcode == BUILD_SET) &&
|
|
codestr[i+3]==COMPARE_OP &&
|
|
ISBASICBLOCK(blocks, h, i-h+6) &&
|
|
(GETARG(codestr,i+3)==6 ||
|
|
GETARG(codestr,i+3)==7))) &&
|
|
tuple_of_constants(&codestr[i], j, consts, CONST_STACK_LASTN(j))) {
|
|
assert(codestr[i] == LOAD_CONST);
|
|
memset(&codestr[h], NOP, i - h);
|
|
CONST_STACK_POP(j);
|
|
CONST_STACK_PUSH_OP(i);
|
|
break;
|
|
}
|
|
if (codestr[i+3] != UNPACK_SEQUENCE ||
|
|
!ISBASICBLOCK(blocks,i,6) ||
|
|
j != GETARG(codestr, i+3) ||
|
|
opcode == BUILD_SET)
|
|
continue;
|
|
if (j == 1) {
|
|
memset(codestr+i, NOP, 6);
|
|
} else if (j == 2) {
|
|
codestr[i] = ROT_TWO;
|
|
memset(codestr+i+1, NOP, 5);
|
|
CONST_STACK_RESET();
|
|
} else if (j == 3) {
|
|
codestr[i] = ROT_THREE;
|
|
codestr[i+1] = ROT_TWO;
|
|
memset(codestr+i+2, NOP, 4);
|
|
CONST_STACK_RESET();
|
|
}
|
|
break;
|
|
|
|
/* Fold binary ops on constants.
|
|
LOAD_CONST c1 LOAD_CONST c2 BINOP --> LOAD_CONST binop(c1,c2) */
|
|
case BINARY_POWER:
|
|
case BINARY_MULTIPLY:
|
|
case BINARY_TRUE_DIVIDE:
|
|
case BINARY_FLOOR_DIVIDE:
|
|
case BINARY_MODULO:
|
|
case BINARY_ADD:
|
|
case BINARY_SUBTRACT:
|
|
case BINARY_SUBSCR:
|
|
case BINARY_LSHIFT:
|
|
case BINARY_RSHIFT:
|
|
case BINARY_AND:
|
|
case BINARY_XOR:
|
|
case BINARY_OR:
|
|
/* NOTE: LOAD_CONST is saved at `i-2` since it has an arg
|
|
while BINOP hasn't */
|
|
h = CONST_STACK_OP_LASTN(2);
|
|
assert((h >= 0 || CONST_STACK_LEN() < 2));
|
|
if (h >= 0 &&
|
|
ISBASICBLOCK(blocks, h, i-h+1) &&
|
|
fold_binops_on_constants(&codestr[i], consts, CONST_STACK_LASTN(2))) {
|
|
i -= 2;
|
|
memset(&codestr[h], NOP, i - h);
|
|
assert(codestr[i] == LOAD_CONST);
|
|
CONST_STACK_POP(2);
|
|
CONST_STACK_PUSH_OP(i);
|
|
}
|
|
break;
|
|
|
|
/* Fold unary ops on constants.
|
|
LOAD_CONST c1 UNARY_OP --> LOAD_CONST unary_op(c) */
|
|
case UNARY_NEGATIVE:
|
|
case UNARY_INVERT:
|
|
case UNARY_POSITIVE:
|
|
h = CONST_STACK_OP_LASTN(1);
|
|
assert((h >= 0 || CONST_STACK_LEN() < 1));
|
|
if (h >= 0 &&
|
|
ISBASICBLOCK(blocks, h, i-h+1) &&
|
|
fold_unaryops_on_constants(&codestr[i-3], consts, CONST_STACK_TOP())) {
|
|
i -= 2;
|
|
assert(codestr[i] == LOAD_CONST);
|
|
CONST_STACK_POP(1);
|
|
CONST_STACK_PUSH_OP(i);
|
|
}
|
|
break;
|
|
|
|
/* Simplify conditional jump to conditional jump where the
|
|
result of the first test implies the success of a similar
|
|
test or the failure of the opposite test.
|
|
Arises in code like:
|
|
"if a and b:"
|
|
"if a or b:"
|
|
"a and b or c"
|
|
"(a and b) and c"
|
|
x:JUMP_IF_FALSE_OR_POP y y:JUMP_IF_FALSE_OR_POP z
|
|
--> x:JUMP_IF_FALSE_OR_POP z
|
|
x:JUMP_IF_FALSE_OR_POP y y:JUMP_IF_TRUE_OR_POP z
|
|
--> x:POP_JUMP_IF_FALSE y+3
|
|
where y+3 is the instruction following the second test.
|
|
*/
|
|
case JUMP_IF_FALSE_OR_POP:
|
|
case JUMP_IF_TRUE_OR_POP:
|
|
tgt = GETJUMPTGT(codestr, i);
|
|
j = codestr[tgt];
|
|
if (CONDITIONAL_JUMP(j)) {
|
|
/* NOTE: all possible jumps here are
|
|
absolute! */
|
|
if (JUMPS_ON_TRUE(j) == JUMPS_ON_TRUE(opcode)) {
|
|
/* The second jump will be
|
|
taken iff the first is. */
|
|
tgttgt = GETJUMPTGT(codestr, tgt);
|
|
/* The current opcode inherits
|
|
its target's stack behaviour */
|
|
codestr[i] = j;
|
|
SETARG(codestr, i, tgttgt);
|
|
goto reoptimize_current;
|
|
} else {
|
|
/* The second jump is not taken
|
|
if the first is (so jump past
|
|
it), and all conditional
|
|
jumps pop their argument when
|
|
they're not taken (so change
|
|
the first jump to pop its
|
|
argument when it's taken). */
|
|
if (JUMPS_ON_TRUE(opcode))
|
|
codestr[i] = POP_JUMP_IF_TRUE;
|
|
else
|
|
codestr[i] = POP_JUMP_IF_FALSE;
|
|
SETARG(codestr, i, (tgt + 3));
|
|
goto reoptimize_current;
|
|
}
|
|
}
|
|
/* Intentional fallthrough */
|
|
|
|
/* Replace jumps to unconditional jumps */
|
|
case POP_JUMP_IF_FALSE:
|
|
case POP_JUMP_IF_TRUE:
|
|
case FOR_ITER:
|
|
case JUMP_FORWARD:
|
|
case JUMP_ABSOLUTE:
|
|
case CONTINUE_LOOP:
|
|
case SETUP_LOOP:
|
|
case SETUP_EXCEPT:
|
|
case SETUP_FINALLY:
|
|
case SETUP_WITH:
|
|
tgt = GETJUMPTGT(codestr, i);
|
|
/* Replace JUMP_* to a RETURN into just a RETURN */
|
|
if (UNCONDITIONAL_JUMP(opcode) &&
|
|
codestr[tgt] == RETURN_VALUE) {
|
|
codestr[i] = RETURN_VALUE;
|
|
memset(codestr+i+1, NOP, 2);
|
|
continue;
|
|
}
|
|
if (!UNCONDITIONAL_JUMP(codestr[tgt]))
|
|
continue;
|
|
tgttgt = GETJUMPTGT(codestr, tgt);
|
|
if (opcode == JUMP_FORWARD) /* JMP_ABS can go backwards */
|
|
opcode = JUMP_ABSOLUTE;
|
|
if (!ABSOLUTE_JUMP(opcode))
|
|
tgttgt -= i + 3; /* Calc relative jump addr */
|
|
if (tgttgt < 0) /* No backward relative jumps */
|
|
continue;
|
|
codestr[i] = opcode;
|
|
SETARG(codestr, i, tgttgt);
|
|
break;
|
|
|
|
case EXTENDED_ARG:
|
|
if (codestr[i+3] != MAKE_FUNCTION)
|
|
goto exitUnchanged;
|
|
/* don't visit MAKE_FUNCTION as GETARG will be wrong */
|
|
i += 3;
|
|
break;
|
|
|
|
/* Replace RETURN LOAD_CONST None RETURN with just RETURN */
|
|
/* Remove unreachable JUMPs after RETURN */
|
|
case RETURN_VALUE:
|
|
if (i+4 >= codelen)
|
|
continue;
|
|
if (codestr[i+4] == RETURN_VALUE &&
|
|
ISBASICBLOCK(blocks,i,5))
|
|
memset(codestr+i+1, NOP, 4);
|
|
else if (UNCONDITIONAL_JUMP(codestr[i+1]) &&
|
|
ISBASICBLOCK(blocks,i,4))
|
|
memset(codestr+i+1, NOP, 3);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Fixup linenotab */
|
|
for (i=0, nops=0 ; i<codelen ; i += CODESIZE(codestr[i])) {
|
|
addrmap[i] = i - nops;
|
|
if (codestr[i] == NOP)
|
|
nops++;
|
|
}
|
|
cum_orig_line = 0;
|
|
last_line = 0;
|
|
for (i=0 ; i < tabsiz ; i+=2) {
|
|
cum_orig_line += lineno[i];
|
|
new_line = addrmap[cum_orig_line];
|
|
assert (new_line - last_line < 255);
|
|
lineno[i] =((unsigned char)(new_line - last_line));
|
|
last_line = new_line;
|
|
}
|
|
|
|
/* Remove NOPs and fixup jump targets */
|
|
for (i=0, h=0 ; i<codelen ; ) {
|
|
opcode = codestr[i];
|
|
switch (opcode) {
|
|
case NOP:
|
|
i++;
|
|
continue;
|
|
|
|
case JUMP_ABSOLUTE:
|
|
case CONTINUE_LOOP:
|
|
case POP_JUMP_IF_FALSE:
|
|
case POP_JUMP_IF_TRUE:
|
|
case JUMP_IF_FALSE_OR_POP:
|
|
case JUMP_IF_TRUE_OR_POP:
|
|
j = addrmap[GETARG(codestr, i)];
|
|
SETARG(codestr, i, j);
|
|
break;
|
|
|
|
case FOR_ITER:
|
|
case JUMP_FORWARD:
|
|
case SETUP_LOOP:
|
|
case SETUP_EXCEPT:
|
|
case SETUP_FINALLY:
|
|
case SETUP_WITH:
|
|
j = addrmap[GETARG(codestr, i) + i + 3] - addrmap[i] - 3;
|
|
SETARG(codestr, i, j);
|
|
break;
|
|
}
|
|
adj = CODESIZE(opcode);
|
|
while (adj--)
|
|
codestr[h++] = codestr[i++];
|
|
}
|
|
assert(h + nops == codelen);
|
|
|
|
code = PyBytes_FromStringAndSize((char *)codestr, h);
|
|
CONST_STACK_DELETE();
|
|
PyMem_Free(addrmap);
|
|
PyMem_Free(codestr);
|
|
PyMem_Free(blocks);
|
|
return code;
|
|
|
|
exitError:
|
|
code = NULL;
|
|
|
|
exitUnchanged:
|
|
CONST_STACK_DELETE();
|
|
if (blocks != NULL)
|
|
PyMem_Free(blocks);
|
|
if (addrmap != NULL)
|
|
PyMem_Free(addrmap);
|
|
if (codestr != NULL)
|
|
PyMem_Free(codestr);
|
|
Py_XINCREF(code);
|
|
return code;
|
|
}
|